The Price to Sales Ratio (P/S Ratio) is a financial metric used to evaluate a company's stock price in relation to its revenue. It is calculated by dividing the market capitalization (the total value of a company's outstanding shares) by its revenue over the last 12 months. The resulting ratio is often used to compare a company's valuation to its industry peers.

A lower P/S ratio may indicate that a stock is undervalued, as the market is placing a lower value on the company's revenue. A higher P/S ratio may indicate that a stock is overvalued, as the market is placing a higher value on the company's revenue.

It's important to note that P/S ratio can vary greatly across industries, a low P/S ratio may be considered good in one industry but in another it may be considered too high. Also, P/S ratio is not always the best indicator of a company's future performance or profitability, as it doesn't take into account a company's debt, earnings or cash flow. It is just one piece of information to consider when evaluating a company's stock and should be used in conjunction with other financial metrics.

Also, P/S ratio can be used as a comparison metric, comparing one company's P/S ratio to its industry average or to P/S ratio of its competitors. This can give an idea of whether the company is overvalued or undervalued compared to its peers. 

An example of using the Price to Sales Ratio (P/S Ratio) to evaluate a company's stock is as follows:

Let's say Company XYZ has a market capitalization of $500 million and generated revenue of $100 million over the last 12 months. To calculate the P/S ratio, we would divide the market capitalization by the revenue:

P/S ratio = $500 million / $100 million = 5

This means that for every dollar of revenue generated by Company XYZ, the market is willing to pay $5 in stock value.

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